This invention relates to improvements in the seat frame of a seat for a vehicle.
The seat frame of a prior art seat for a vehicle is such that flanges are integrally formed at the upper end of a peripheral wall composed of flat erect wall portions, and that mounting holes or the like for a spring base are directly provided in the flange portions. With such structure, however, the body-weight of an occupant acts as an inward tensile load on the upper end of the peripheral wall through the spring base, so that such deformation as throws the peripheral wall down inwards is prone to occur. Another disadvantage is that stresses ascribable to the load are concentrated on the mounting holes of the flange portions and that the seat frame is easily damaged from the mounting hole part. In order to prevent the deformation and the damage, the seat frame has been fabricated of a steel plate being as thick as 1.2 mm. The use of such thick steel plate incurs increase in the amount of consumption of steel plates, increase in labor in the handling of the seat as attributed to the increase of weight, increase in the amount of fuel consumption, etc.
An object of this invention to provide a seat frame in which even when the peripheral wall thereof is subjected to an intense inward tensile load, it is not turned inwards and is prevented from being deformed or damaged. Another object of this invention is to provide a seat frame which can be fabricated of a thinner metal plate than in the prior art seat frame and is remarkably excellent from the standpoint of material and weight. A further object is to provide the optimum shape and structure for the integral molding of a seat frame with a press and to thereby enhance the productivity.